Find the limit by evaluating the derivative of a suitable function at an appropriate point? lim t approaches 0 (1-(1+t)^2/t(1+t)^2) Thank you very much

Do you mean lim_(t to 0)(1-(1+t)^2/(t(1+t)^2))

2 Answers
May 28, 2018

color(blue)[lim_(t to 0)((1-(1+t)^2)/(t(1+t)^2))=lim_(t to 0)[-2(1+t)]/[t*2(1+t)+(1+t)^2]=-2/1=-2]

Explanation:

I assume it is lim_(t to 0)((1-(1+t)^2)/(t(1+t)^2))

lim_(t to 0)((1-(1+t)^2)/(t(1+t)^2))=0/0

since the direct compensation product equal 0/0
we will use L'hospital Rule.
L'hospital Rule color(red)[lim_(trarra)(f'(x))/(g'(x))]

now lets applied L'hospital Rule.

lim_(t to 0)((1-(1+t)^2)/(t(1+t)^2))=lim_(t to 0)[-2(1+t)]/[t*2(1+t)+(1+t)^2]=-2/1=-2

May 28, 2018

lim_(t to 0) (1-(1+t)^2)/(t(1+t)^2) = -2

Explanation:

If we seek the value of the corrected limit:

L = lim_(t to 0) (1-(1+t)^2)/(t(1+t)^2)

Then by expanding the numerator, we have:

L = lim_(t to 0) (1-(1+2t+t^2))/(t(1+t)^2)

\ \ = lim_(t to 0) (-2t-t^2)/(t(1+t)^2)

\ \ = lim_(t to 0) (-t(2+t))/(t(1+t)^2)

\ \ = lim_(t to 0) (-(2+t))/((1+t)^2)

And we can evaluate this limit by direct substitution:

L = (-(2+0))/((1+0)^2)
\ \ = -2